1. Field of the Invention
The present invention relates to a multilayer wiring substrate having a laminated structure composed of conductor layers and resin insulating layers alternately stacked, and to a method for manufacturing the same.
2. Description of Related Art
In recent years, semiconductor integrated circuit elements (IC chips) used as microprocessors of computers or the like have been enhanced in speed and function more and more, and, thus, IC chips tend to have an increased number of terminals and a reduced inter-terminal pitch. In general, a large number of terminals are densely disposed in an array on the bottom surface of an IC chip. Such a group of terminals are flip-chip connected to a group of terminals on the motherboard. However, since the inter-terminal pitch differs greatly between the IC chip side terminal group and the motherboard side terminal group, difficultly is encountered in connecting the IC chip directly onto the motherboard. Therefore, in general, a semiconductor package including an IC chip mounted on an IC-chip mounting wiring substrate is fabricated, and is then mounted on a motherboard (see, for example, Japanese Patent Application Laid-Open (kokai) No. 2002-26500 (FIG. 1, etc.)).
Notably, an IC-chip mounting wiring substrate is manufactured, for example, through the following steps. First, a copper foil layer is disposed on a support substrate, and a predetermined mask is disposed on the copper foil layer. Subsequently, a gold layer, a nickel layer, and a copper layer are stacked, in this sequence, on portions of the copper foil layer exposed from the opening portions of the mask. As a result, surface connection terminals, on which solder bumps for connection of an IC chip are disposed, are formed (terminal forming step). Subsequently, after the mask is removed, a resin insulating layer for covering the surface connection terminals is formed on the support substrate (resin-insulating-layer forming step). Further, via conductors connected to the surface connection terminals are formed in the resin insulating layer. Conductor layers and resin insulating layers are alternately stacked so as to form a laminated structure. After that, the support substrate is peeled off, and the copper foil layer is removed through etching (removal step), whereby a multilayer wiring substrate having a laminated structure can be obtained.